Breadcrumb

A shocking way to study stream health: MSD and electro-fishing

November 8, 2017

Rainfall. Temperature. Man-made pollutants. Numerous factors can affect the life of a stream, which means Louisville MSD must utilize a variety of tools to understand stream health and water quality as part of its mission to ensure safe, clean waterways.

One such method is a scientific survey method known as electro-fishing, as part of its efforts to collect biological data about streams in the Louisville Metro area. Fish, along with other biological data, provides insight on local stream health. The process involves using electricity to stun fish before they are caught.

The method is used to sample fish populations, and fish are returned to the stream unharmed in as little as 10 minutes after being stunned. One person operates the equipment that stuns the fish while others catch the stunned fish with a net and place them in a bucket of stream water. The fish are identified and then returned to the stream.

Erin Wagoner, a project administrator for MSD, said the process allows teams to look at the types and numbers of fish in individual streams. Fish are good biological indicators of long-term stream health. Their mobility allows them to travel upstream or downstream to stream reaches that suit their growth and survival.

“Some fish species are more sensitive to pollution and other species are more tolerant,” Wagoner said. “For example, streams draining from less urban watersheds that have good tree cover and habitat tend to have better in-stream water quality.”

Another method used to collect biological data is the placement of ceramic tiles in the stream bottom. Tiles are left in place at least 15 days, allowing algae to grow on the tiles. The tiles are then collected and the algae studied in a laboratory. Both survey methods are conducted every two years as part of Louisville MSD’s monitoring of water quality and stream health throughout Louisville Metro. MSD has collected physical, chemical and biological stream data at 27 locations since 1999. The sites were selected to represent streams in each our community’s 11 watersheds.

“By collecting this long-term data, we can see whether the water quality of our streams is improving or declining,” Wagoner said. “Then we can make decisions on where to focus efforts, and how to gauge success in improving stream quality.”

As an urban community, stormwater runoff is a primary contributor to the health of our streams. Planting a tree, encouraging stream buffer zones, limiting fertilizer and pesticide use, and picking up after our pets can all have a positive influence on downstream water quality conditions.